Thanks, but the reverse keys are asymetric like the forward keys? The reverse keys are similar to forward keys?.
– francisco dominguezJul 13 '16 at 13:41

The reverse and forward keys are a pair of symmetric keys. The key exchange (TAP or nTor) is done using asymmetric/public key cryptography, the keys derived from the key exchange are symmetric, specifically they are used as AES keys.
– cacahuatlJul 13 '16 at 15:48

Does this first TLS connection not use the TAP/Ntor protocol?
– forestFeb 17 at 11:55